In certain processes, such as dehydrogenation of alkanes or alkyl aromatics, it is important to minimize the residence time of the molecules at reaction temperature. In a fluidized reactor system, the fluidized catalyst and product gas must also be rapidly separated to avoid further degradation of the unreacted alkane or alkyl aromatics and the products produced. Fluidized reactor designs generally have gas residence time greater than 1 second. Such a long residence time could have a large impact on reaction yield. For example, a 1 second residence time in a propane dehydrogenation process at reaction temperature would cause a selectivity penalty of about 0.7 mol %. Attempts to minimize residence time must be balanced with the need for mechanical and thermal stability in supporting the cyclones at high temperatures which balances the thermal expansion within the system.